/*
* Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
/* 2001-09-28...2002-04-17
* Partition stuff by James_McMechan@hotmail.com
* old style ubd by setting UBD_SHIFT to 0
* 2002-09-27...2002-10-18 massive tinkering for 2.5
* partitions have changed in 2.5
*/
#define MAJOR_NR UBD_MAJOR
#define UBD_SHIFT 4
#include "linux/config.h"
#include "linux/module.h"
#include "linux/blkdev.h"
#include "linux/hdreg.h"
#include "linux/init.h"
#include "linux/devfs_fs_kernel.h"
#include "linux/cdrom.h"
#include "linux/proc_fs.h"
#include "linux/ctype.h"
#include "linux/capability.h"
#include "linux/mm.h"
#include "linux/vmalloc.h"
#include "linux/blkpg.h"
#include "linux/genhd.h"
#include "linux/spinlock.h"
#include "asm/segment.h"
#include "asm/uaccess.h"
#include "asm/irq.h"
#include "asm/types.h"
#include "asm/tlbflush.h"
#include "user_util.h"
#include "mem_user.h"
#include "kern_util.h"
#include "kern.h"
#include "mconsole_kern.h"
#include "init.h"
#include "irq_user.h"
#include "ubd_user.h"
#include "2_5compat.h"
#include "os.h"
static spinlock_t ubd_io_lock = SPIN_LOCK_UNLOCKED;
static spinlock_t ubd_lock = SPIN_LOCK_UNLOCKED;
static void (*do_ubd)(void);
static int ubd_open(struct inode * inode, struct file * filp);
static int ubd_release(struct inode * inode, struct file * file);
static int ubd_ioctl(struct inode * inode, struct file * file,
unsigned int cmd, unsigned long arg);
#define MAX_DEV (8)
static struct block_device_operations ubd_blops = {
.owner = THIS_MODULE,
.open = ubd_open,
.release = ubd_release,
.ioctl = ubd_ioctl,
};
/* Protected by the queue_lock */
static request_queue_t *ubd_queue;
/* Protected by ubd_lock */
static int fake_major = 0;
static struct gendisk *ubd_gendisk[MAX_DEV];
static struct gendisk *fake_gendisk[MAX_DEV];
#ifdef CONFIG_BLK_DEV_UBD_SYNC
#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
.cl = 1 })
#else
#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
.cl = 1 })
#endif
/* Not protected - changed only in ubd_setup_common and then only to
* to enable O_SYNC.
*/
static struct openflags global_openflags = OPEN_FLAGS;
struct cow {
char *file;
int fd;
unsigned long *bitmap;
unsigned long bitmap_len;
int bitmap_offset;
int data_offset;
};
struct ubd {
char *file;
int is_dir;
int count;
int fd;
__u64 size;
struct openflags boot_openflags;
struct openflags openflags;
struct cow cow;
};
#define DEFAULT_COW { \
.file = NULL, \
.fd = -1, \
.bitmap = NULL, \
.bitmap_offset = 0, \
.data_offset = 0, \
}
#define DEFAULT_UBD { \
.file = NULL, \
.is_dir = 0, \
.count = 0, \
.fd = -1, \
.size = -1, \
.boot_openflags = OPEN_FLAGS, \
.openflags = OPEN_FLAGS, \
.cow = DEFAULT_COW, \
}
struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD };
static int ubd0_init(void)
{
if(ubd_dev[0].file == NULL)
ubd_dev[0].file = "root_fs";
return(0);
}
__initcall(ubd0_init);
/* Only changed by fake_ide_setup which is a setup */
static int fake_ide = 0;
static struct proc_dir_entry *proc_ide_root = NULL;
static struct proc_dir_entry *proc_ide = NULL;
static void make_proc_ide(void)
{
proc_ide_root = proc_mkdir("ide", 0);
proc_ide = proc_mkdir("ide0", proc_ide_root);
}
static int proc_ide_read_media(char *page, char **start, off_t off, int count,
int *eof, void *data)
{
int len;
strcpy(page, "disk\n");
len = strlen("disk\n");
len -= off;
if (len < count){
*eof = 1;
if (len <= 0) return 0;
}
else len = count;
*start = page + off;
return len;
}
static void make_ide_entries(char *dev_name)
{
struct proc_dir_entry *dir, *ent;
char name[64];
if(proc_ide_root == NULL) make_proc_ide();
dir = proc_mkdir(dev_name, proc_ide);
if(!dir) return;
ent = create_proc_entry("media", S_IFREG|S_IRUGO, dir);
if(!ent) return;
ent->nlink = 1;
ent->data = NULL;
ent->read_proc = proc_ide_read_media;
ent->write_proc = NULL;
sprintf(name,"ide0/%s", dev_name);
proc_symlink(dev_name, proc_ide_root, name);
}
static int fake_ide_setup(char *str)
{
fake_ide = 1;
return(1);
}
__setup("fake_ide", fake_ide_setup);
__uml_help(fake_ide_setup,
"fake_ide\n"
" Create ide0 entries that map onto ubd devices.\n\n"
);
static int ubd_setup_common(char *str, int *index_out)
{
struct openflags flags = global_openflags;
char *backing_file;
int n, err;
if(index_out) *index_out = -1;
n = *str++;
if(n == '='){
static int fake_major_allowed = 1;
char *end;
int major;
if(!strcmp(str, "sync")){
global_openflags.s = 1;
return(0);
}
major = simple_strtoul(str, &end, 0);
if((*end != '\0') || (end == str)){
printk(KERN_ERR
"ubd_setup : didn't parse major number\n");
return(1);
}
if(!fake_major_allowed){
printk(KERN_ERR "Can't assign a fake major twice\n");
return(1);
}
err = 1;
spin_lock(&ubd_lock);
if(!fake_major_allowed){
printk(KERN_ERR "Can't assign a fake major twice\n");
goto out1;
}
fake_major = major;
fake_major_allowed = 0;
printk(KERN_INFO "Setting extra ubd major number to %d\n",
major);
err = 0;
out1:
spin_unlock(&ubd_lock);
return(err);
}
if(n < '0'){
printk(KERN_ERR "ubd_setup : index out of range\n"); }
if((n >= '0') && (n <= '9')) n -= '0';
else if((n >= 'a') && (n <= 'z')) n -= 'a';
else {
printk(KERN_ERR "ubd_setup : device syntax invalid\n");
return(1);
}
if(n >= MAX_DEV){
printk(KERN_ERR "ubd_setup : index out of range "
"(%d devices)\n", MAX_DEV);
return(1);
}
err = 1;
spin_lock(&ubd_lock);
if(ubd_dev[n].file != NULL){
printk(KERN_ERR "ubd_setup : device already configured\n");
goto out2;
}
if(index_out) *index_out = n;
if (*str == 'r'){
flags.w = 0;
str++;
}
if (*str == 's'){
flags.s = 1;
str++;
}
if(*str++ != '='){
printk(KERN_ERR "ubd_setup : Expected '='\n");
goto out2;
}
err = 0;
backing_file = strchr(str, ',');
if(backing_file){
*backing_file = '\0';
backing_file++;
}
ubd_dev[n].file = str;
if(ubd_is_dir(ubd_dev[n].file))
ubd_dev[n].is_dir = 1;
ubd_dev[n].cow.file = backing_file;
ubd_dev[n].boot_openflags = flags;
out2:
spin_unlock(&ubd_lock);
return(err);
}
static int ubd_setup(char *str)
{
ubd_setup_common(str, NULL);
return(1);
}
__setup("ubd", ubd_setup);
__uml_help(ubd_setup,
"ubd<n>=<filename>\n"
" This is used to associate a device with a file in the underlying\n"
" filesystem. Usually, there is a filesystem in the file, but \n"
" that's not required. Swap devices containing swap files can be\n"
" specified like this. Also, a file which doesn't contain a\n"
" filesystem can have its contents read in the virtual \n"
" machine by running dd on the device. n must be in the range\n"
" 0 to 7. Appending an 'r' to the number will cause that device\n"
" to be mounted read-only. For example ubd1r=./ext_fs. Appending\n"
" an 's' (has to be _after_ 'r', if there is one) will cause data\n"
" to be written to disk on the host immediately.\n\n"
);
static int fakehd_set = 0;
static int fakehd(char *str)
{
printk(KERN_INFO
"fakehd : Changing ubd name to \"hd\".\n");
fakehd_set = 1;
return 1;
}
__setup("fakehd", fakehd);
__uml_help(fakehd,
"fakehd\n"
" Change the ubd device name to \"hd\".\n\n"
);
static void do_ubd_request(request_queue_t * q);
/* Only changed by ubd_init, which is an initcall. */
int thread_fd = -1;
/* Changed by ubd_handler, which is serialized because interrupts only
* happen on CPU 0.
*/
int intr_count = 0;
static void ubd_finish(struct request *req, int error)
{
int nsect;
if(error){
spin_lock(&ubd_io_lock);
end_request(req, 0);
spin_unlock(&ubd_io_lock);
return;
}
nsect = req->current_nr_sectors;
req->sector += nsect;
req->buffer += nsect << 9;
req->errors = 0;
req->nr_sectors -= nsect;
req->current_nr_sectors = 0;
spin_lock(&ubd_io_lock);
end_request(req, 1);
spin_unlock(&ubd_io_lock);
}
static void ubd_handler(void)
{
struct io_thread_req req;
struct request *rq = elv_next_request(ubd_queue);
int n;
do_ubd = NULL;
intr_count++;
n = read_ubd_fs(thread_fd, &req, sizeof(req));
if(n != sizeof(req)){
printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, "
"errno = %d\n", os_getpid(), -n);
spin_lock(&ubd_io_lock);
end_request(rq, 0);
spin_unlock(&ubd_io_lock);
return;
}
if((req.offset != ((__u64) (rq->sector)) << 9) ||
(req.length != (rq->current_nr_sectors) << 9))
panic("I/O op mismatch");
ubd_finish(rq, req.error);
reactivate_fd(thread_fd, UBD_IRQ);
do_ubd_request(ubd_queue);
}
static void ubd_intr(int irq, void *dev, struct pt_regs *unused)
{
ubd_handler();
}
/* Only changed by ubd_init, which is an initcall. */
static int io_pid = -1;
void kill_io_thread(void)
{
if(io_pid != -1)
os_kill_process(io_pid, 1);
}
__uml_exitcall(kill_io_thread);
static int ubd_file_size(struct ubd *dev, __u64 *size_out)
{
char *file;
file = dev->cow.file ? dev->cow.file : dev->file;
return(os_file_size(file, size_out));
}
static void ubd_close(struct ubd *dev)
{
os_close_file(dev->fd);
if(dev->cow.file == NULL)
return;
os_close_file(dev->cow.fd);
vfree(dev->cow.bitmap);
dev->cow.bitmap = NULL;
}
static int ubd_open_dev(struct ubd *dev)
{
struct openflags flags;
int err, n, create_cow, *create_ptr;
create_cow = 0;
create_ptr = (dev->cow.file != NULL) ? &create_cow : NULL;
dev->fd = open_ubd_file(dev->file, &dev->openflags, &dev->cow.file,
&dev->cow.bitmap_offset, &dev->cow.bitmap_len,
&dev->cow.data_offset, create_ptr);
if((dev->fd == -ENOENT) && create_cow){
n = dev - ubd_dev;
dev->fd = create_cow_file(dev->file, dev->cow.file,
dev->openflags, 1 << 9,
&dev->cow.bitmap_offset,
&dev->cow.bitmap_len,
&dev->cow.data_offset);
if(dev->fd >= 0){
printk(KERN_INFO "Creating \"%s\" as COW file for "
"\"%s\"\n", dev->file, dev->cow.file);
}
}
if(dev->fd < 0) return(dev->fd);
if(dev->cow.file != NULL){
err = -ENOMEM;
dev->cow.bitmap = (void *) vmalloc(dev->cow.bitmap_len);
if(dev->cow.bitmap == NULL) goto error;
flush_tlb_kernel_vm();
err = read_cow_bitmap(dev->fd, dev->cow.bitmap,
dev->cow.bitmap_offset,
dev->cow.bitmap_len);
if(err) goto error;
flags = dev->openflags;
flags.w = 0;
err = open_ubd_file(dev->cow.file, &flags, NULL, NULL, NULL,
NULL, NULL);
if(err < 0) goto error;
dev->cow.fd = err;
}
return(0);
error:
os_close_file(dev->fd);
return(err);
}
static int ubd_new_disk(int major, u64 size, int unit,
struct gendisk **disk_out)
{
struct gendisk *disk;
disk = alloc_disk(1 << UBD_SHIFT);
if (!disk)
return -ENOMEM;
disk->major = major;
disk->first_minor = unit << UBD_SHIFT;
disk->fops = &ubd_blops;
set_capacity(disk, size / 512);
sprintf(disk->disk_name, "ubd");
sprintf(disk->devfs_name, "ubd/disc%d", unit);
disk->private_data = &ubd_dev[unit];
disk->queue = ubd_queue;
add_disk(disk);
*disk_out = disk;
return 0;
}
static int ubd_add(int n)
{
struct ubd *dev = &ubd_dev[n];
int err;
if(dev->is_dir)
return(-EISDIR);
if (!dev->file)
return(-ENODEV);
if (ubd_open_dev(dev))
return(-ENODEV);
err = ubd_file_size(dev, &dev->size);
if(err)
return(err);
err = ubd_new_disk(MAJOR_NR, dev->size, n, &ubd_gendisk[n]);
if(err)
return(err);
if(fake_major)
ubd_new_disk(fake_major, dev->size, n,
&fake_gendisk[n]);
/* perhaps this should also be under the "if (fake_major)" above */
/* using the fake_disk->disk_name and also the fakehd_set name */
if (fake_ide)
make_ide_entries(ubd_gendisk[n]->disk_name);
ubd_close(dev);
return 0;
}
static int ubd_config(char *str)
{
int n, err;
str = uml_strdup(str);
if(str == NULL){
printk(KERN_ERR "ubd_config failed to strdup string\n");
return(1);
}
err = ubd_setup_common(str, &n);
if(err){
kfree(str);
return(-1);
}
if(n == -1) return(0);
spin_lock(&ubd_lock);
err = ubd_add(n);
if(err)
ubd_dev[n].file = NULL;
spin_unlock(&ubd_lock);
return(err);
}
static int ubd_get_config(char *dev, char *str, int size, char **error_out)
{
struct ubd *ubd;
char *end;
int major, n = 0;
major = simple_strtoul(dev, &end, 0);
if((*end != '\0') || (end == dev)){
*error_out = "ubd_get_config : didn't parse major number";
return(-1);
}
if((major >= MAX_DEV) || (major < 0)){
*error_out = "ubd_get_config : major number out of range";
return(-1);
}
ubd = &ubd_dev[major];
spin_lock(&ubd_lock);
if(ubd->file == NULL){
CONFIG_CHUNK(str, size, n, "", 1);
goto out;
}
CONFIG_CHUNK(str, size, n, ubd->file, 0);
if(ubd->cow.file != NULL){
CONFIG_CHUNK(str, size, n, ",", 0);
CONFIG_CHUNK(str, size, n, ubd->cow.file, 1);
}
else CONFIG_CHUNK(str, size, n, "", 1);
out:
spin_unlock(&ubd_lock);
return(n);
}
static int ubd_remove(char *str)
{
struct ubd *dev;
int n, err = -ENODEV;
if(!isdigit(*str))
return(err); /* it should be a number 0-7/a-h */
n = *str - '0';
if(n >= MAX_DEV)
return(err);
dev = &ubd_dev[n];
if(dev->count > 0)
return(-EBUSY); /* you cannot remove a open disk */
err = 0;
spin_lock(&ubd_lock);
if(ubd_gendisk[n] == NULL)
goto out;
del_gendisk(ubd_gendisk[n]);
put_disk(ubd_gendisk[n]);
ubd_gendisk[n] = NULL;
if(fake_gendisk[n] != NULL){
del_gendisk(fake_gendisk[n]);
put_disk(fake_gendisk[n]);
fake_gendisk[n] = NULL;
}
*dev = ((struct ubd) DEFAULT_UBD);
err = 0;
out:
spin_unlock(&ubd_lock);
return(err);
}
static struct mc_device ubd_mc = {
.name = "ubd",
.config = ubd_config,
.get_config = ubd_get_config,
.remove = ubd_remove,
};
static int ubd_mc_init(void)
{
mconsole_register_dev(&ubd_mc);
return 0;
}
__initcall(ubd_mc_init);
int ubd_init(void)
{
int i;
devfs_mk_dir("ubd");
if (register_blkdev(MAJOR_NR, "ubd"))
return -1;
ubd_queue = blk_init_queue(do_ubd_request, &ubd_io_lock);
if (!ubd_queue) {
unregister_blkdev(MAJOR_NR, "ubd");
return -1;
}
elevator_init(ubd_queue, &elevator_noop);
if (fake_major != 0) {
char name[sizeof("ubd_nnn\0")];
snprintf(name, sizeof(name), "ubd_%d", fake_major);
devfs_mk_dir(name);
if (register_blkdev(fake_major, "ubd"))
return -1;
}
for (i = 0; i < MAX_DEV; i++)
ubd_add(i);
return 0;
}
late_initcall(ubd_init);
int ubd_driver_init(void){
unsigned long stack;
int err;
if(global_openflags.s){
printk(KERN_INFO "ubd : Synchronous mode\n");
return(0);
}
stack = alloc_stack(0, 0);
io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *),
&thread_fd);
if(io_pid < 0){
printk(KERN_ERR
"ubd : Failed to start I/O thread (errno = %d) - "
"falling back to synchronous I/O\n", -io_pid);
return(0);
}
err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
SA_INTERRUPT, "ubd", ubd_dev);
if(err != 0) printk(KERN_ERR
"um_request_irq failed - errno = %d\n", -err);
return(err);
}
device_initcall(ubd_driver_init);
static int ubd_open(struct inode *inode, struct file *filp)
{
struct gendisk *disk = inode->i_bdev->bd_disk;
struct ubd *dev = disk->private_data;
int err = -EISDIR;
if(dev->is_dir == 1)
goto out;
err = 0;
if(dev->count == 0){
dev->openflags = dev->boot_openflags;
err = ubd_open_dev(dev);
if(err){
printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n",
disk->disk_name, dev->file, -err);
goto out;
}
}
dev->count++;
if((filp->f_mode & FMODE_WRITE) && !dev->openflags.w){
if(--dev->count == 0) ubd_close(dev);
err = -EROFS;
}
out:
return(err);
}
static int ubd_release(struct inode * inode, struct file * file)
{
struct gendisk *disk = inode->i_bdev->bd_disk;
struct ubd *dev = disk->private_data;
if(--dev->count == 0)
ubd_close(dev);
return(0);
}
void cowify_req(struct io_thread_req *req, struct ubd *dev)
{
int i, update_bitmap, sector = req->offset >> 9;
if(req->length > (sizeof(req->sector_mask) * 8) << 9)
panic("Operation too long");
if(req->op == UBD_READ) {
for(i = 0; i < req->length >> 9; i++){
if(ubd_test_bit(sector + i, (unsigned char *)
dev->cow.bitmap)){
ubd_set_bit(i, (unsigned char *)
&req->sector_mask);
}
}
}
else {
update_bitmap = 0;
for(i = 0; i < req->length >> 9; i++){
ubd_set_bit(i, (unsigned char *)
&req->sector_mask);
if(!ubd_test_bit(sector + i, (unsigned char *)
dev->cow.bitmap))
update_bitmap = 1;
ubd_set_bit(sector + i, (unsigned char *)
dev->cow.bitmap);
}
if(update_bitmap){
req->cow_offset = sector / (sizeof(unsigned long) * 8);
req->bitmap_words[0] =
dev->cow.bitmap[req->cow_offset];
req->bitmap_words[1] =
dev->cow.bitmap[req->cow_offset + 1];
req->cow_offset *= sizeof(unsigned long);
req->cow_offset += dev->cow.bitmap_offset;
}
}
}
static int prepare_request(struct request *req, struct io_thread_req *io_req)
{
struct gendisk *disk = req->rq_disk;
struct ubd *dev = disk->private_data;
__u64 block;
int nsect;
if(req->rq_status == RQ_INACTIVE) return(1);
if(dev->is_dir){
strcpy(req->buffer, "HOSTFS:");
strcat(req->buffer, dev->file);
spin_lock(&ubd_io_lock);
end_request(req, 1);
spin_unlock(&ubd_io_lock);
return(1);
}
if((rq_data_dir(req) == WRITE) && !dev->openflags.w){
printk("Write attempted on readonly ubd device %s\n",
disk->disk_name);
spin_lock(&ubd_io_lock);
end_request(req, 0);
spin_unlock(&ubd_io_lock);
return(1);
}
block = req->sector;
nsect = req->current_nr_sectors;
io_req->op = rq_data_dir(req) == READ ? UBD_READ : UBD_WRITE;
io_req->fds[0] = (dev->cow.file != NULL) ? dev->cow.fd : dev->fd;
io_req->fds[1] = dev->fd;
io_req->offsets[0] = 0;
io_req->offsets[1] = dev->cow.data_offset;
io_req->offset = ((__u64) block) << 9;
io_req->length = nsect << 9;
io_req->buffer = req->buffer;
io_req->sectorsize = 1 << 9;
io_req->sector_mask = 0;
io_req->cow_offset = -1;
io_req->error = 0;
if(dev->cow.file != NULL) cowify_req(io_req, dev);
return(0);
}
static void do_ubd_request(request_queue_t *q)
{
struct io_thread_req io_req;
struct request *req;
int err, n;
if(thread_fd == -1){
while(!list_empty(&q->queue_head)){
req = elv_next_request(q);
err = prepare_request(req, &io_req);
if(!err){
do_io(&io_req);
ubd_finish(req, io_req.error);
}
}
}
else {
if(do_ubd || list_empty(&q->queue_head)) return;
req = elv_next_request(q);
err = prepare_request(req, &io_req);
if(!err){
do_ubd = ubd_handler;
n = write_ubd_fs(thread_fd, (char *) &io_req,
sizeof(io_req));
if(n != sizeof(io_req))
printk("write to io thread failed, "
"errno = %d\n", -n);
}
}
}
static int ubd_ioctl(struct inode * inode, struct file * file,
unsigned int cmd, unsigned long arg)
{
struct hd_geometry *loc = (struct hd_geometry *) arg;
struct ubd *dev = inode->i_bdev->bd_disk->private_data;
int err;
struct hd_driveid ubd_id = {
.cyls = 0,
.heads = 128,
.sectors = 32,
};
switch (cmd) {
struct hd_geometry g;
struct cdrom_volctrl volume;
case HDIO_GETGEO:
if(!loc) return(-EINVAL);
g.heads = 128;
g.sectors = 32;
g.cylinders = dev->size / (128 * 32 * 512);
g.start = 2;
return(copy_to_user(loc, &g, sizeof(g)) ? -EFAULT : 0);
case HDIO_SET_UNMASKINTR:
if(!capable(CAP_SYS_ADMIN)) return(-EACCES);
if((arg > 1) || (inode->i_bdev->bd_contains != inode->i_bdev))
return(-EINVAL);
return(0);
case HDIO_GET_UNMASKINTR:
if(!arg) return(-EINVAL);
err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long));
if(err)
return(err);
return(0);
case HDIO_GET_MULTCOUNT:
if(!arg) return(-EINVAL);
err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long));
if(err)
return(err);
return(0);
case HDIO_SET_MULTCOUNT:
if(!capable(CAP_SYS_ADMIN)) return(-EACCES);
if(inode->i_bdev->bd_contains != inode->i_bdev)
return(-EINVAL);
return(0);
case HDIO_GET_IDENTITY:
ubd_id.cyls = dev->size / (128 * 32 * 512);
if(copy_to_user((char *) arg, (char *) &ubd_id,
sizeof(ubd_id)))
return(-EFAULT);
return(0);
case CDROMVOLREAD:
if(copy_from_user(&volume, (char *) arg, sizeof(volume)))
return(-EFAULT);
volume.channel0 = 255;
volume.channel1 = 255;
volume.channel2 = 255;
volume.channel3 = 255;
if(copy_to_user((char *) arg, &volume, sizeof(volume)))
return(-EFAULT);
return(0);
}
return(-EINVAL);
}
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/
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